Monomer–Dimer Equilibrium for the 5′–5′ Stacking of Propeller-Type Parallel-Stranded G-Quadruplexes: NMR Structural Study

Authors

  • Ngoc Quang Do,

    1. School of Physical and Mathematical Sciences, Nanyang Technological University, 637371 (Singapore), Fax: (+65) 6795-7981
    2. School of Biological Sciences, Nanyang Technological University, 637551 (Singapore)
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  • Prof. Dr. Anh Tuân Phan

    Corresponding author
    1. School of Physical and Mathematical Sciences, Nanyang Technological University, 637371 (Singapore), Fax: (+65) 6795-7981
    • School of Physical and Mathematical Sciences, Nanyang Technological University, 637371 (Singapore), Fax: (+65) 6795-7981
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Abstract

Guanine-rich sequence motifs, which contain tracts of three consecutive guanines connected by single non-guanine nucleotides, are abundant in the human genome and can form a robust G-quadruplex structure with high stability. Herein, by using NMR spectroscopy, we investigate the equilibrium between monomeric and 5′–5′ stacked dimeric propeller-type G-quadruplexes that are formed by DNA sequences containing GGGT motifs. We show that the monomer–dimer equilibrium depends on a number of parameters, including the DNA concentration, DNA flanking sequences, the concentration and type of cations, and the temperature. We report on the high-definition structure of a simple monomeric G-quadruplex containing three single-residue loops, which could serve as a reference for propeller-type G-quadruplex structures in solution.

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